Abstract

Zika virus (ZIKV) is an emerging mosquito-borne pathogen. ZIKV infection is linked to thedevelopment of severe fetal abnormalities that include spontaneous abortion, stillbirth, hydranencephaly, and microcephaly. ZIKV outbreaks have been recorded in the United States.We recently demonstrated the first congenital ZIKV infection in the United States. In thisstudy, we investigated archived blood samples from six mothers who gave birth to babieswith microcephaly and 12 mothers who gave birth to healthy babies in Hawaii between 2009and 2012. We tested maternal blood for the presence of ZIKV IgM and IgG antibodies usingcommercially available human ZIKV IgM and IgG ELISA kits. Blood from one mother whodelivered babies with microcephaly tested positive for ZIKV IgM antibody (16.6%) and bloodfrom three mothers tested positive for ZIKV IgG antibody (50%). ZIKV showed a trend towardsignificance with microcephaly. ZIKV IgG antibody positive mothers were more likely todeliver babies with microcephaly than mothers who were negative for ZIKV IgG antibodies(Odds ratio [OR] = 11.0, 95% confidence interval [CI] = 0.8Ã?Â±147.9, p = 0.083). Similarly, ZIKVIgM antibody positive mothers were also more likely to deliver babies with microcephaly thanmothers who were negative for ZIKV IgM antibody (OR = 6.8, 95% CI = 0.2Ã?Â±195.1). Thesedata provide further evidence of a link between ZIKV infection and microcephaly and suggestspresence of ZIKV positive cases and associated microcephaly in the United States asearly as 2009.